Electrical signal delay device



Nov. 17, 1953 w. M. ALLISON ELECTRICAL SIGNAL DELAY DEVICE Filed April 18, 1951 INVENTOR. I V/ZU/IM M /////60/V Patented Nov. 17, 1953 ELECTRICAL SIGNAL DELAY DEVICE William M. Allison, North Adams, Mass., assignor to Sprague Electric Company, North Adams, Mass., a corporation of Massachusetts Application April 18, 1951, Serial No. 221,660

' 8 Claims. 1

The present invention relates to delay devices. and more particularly to such devices in which electrical signals are given a desired time delay.

Among the objects of the present invention is the provision of novel delay devices that provide characteristic delay patterns.

A further object of the present invention is the provision of compact delay devices that are more convenient to use.

The above as well as additional objects of the present invention will be more 'fully understood from the following description of several of its exemplifications, reference being made to the accompanying drawings wherein:

Fig. 1 is a perspective view of one form of delay device of the present invention with signal supply and output components shown diagrammatically; and

Fig. 2 is a plan view of a modified form of delay element embodying the present invention.

In accordance with the present invention a signal delay device is arranged to provide an endless or ring-shaped delay path so that signals supplied at one portion of the path travel around it in opposite directions and are repeated in a characteristic manner when picked up from other portions of the path.

Signal delaying devices have been applied to many diiTerent uses in the electrical communication and allied fields. Thus in identification systems for use with pulse-echo radar detection units, delaying devices can be used to repeat beacon signals from detected stations or for matching the time delay injected into the beacon signals by the beacon stations. Also, as indicated in Patent No. 2,495,740, granted January 31, 1950, delay devices are suitable for repeating multiplex signal transmission pulses.

In accordance with the present invention the ring-shaped character of the delay device causes impressed signals to travel one or more times around the ring in each direction so that a suitably located thansducer picks up a succession of characteristically spaced signals. The number of signals in the succession depends on the attenuation of the signals as they travel around the ring.

Referring to Fig. 1, there is here shown a signal-carrying transducer ring to of piezo-electric material, in this case a barium-strontium titanate having 23% strontium titanate. The ring is fiat and has on opposed portions of its flat faces a set of electrically conductive terminal or electrode pairs [2, l3, l4, !5, IE, l1, l8, I9. These terminals are suitably held in place as by being fired directly on the ceramic body of the ring.

Signals are supplied to one pair of terminals I2, l3 by unit so which can be any suitable type of pulse signal generator, and can :be taken from any of the other electrode pairs and delivered to the desired signal-utilizing circuit shown in the figure :as the signal output 48. Within the electrical input ring the signals are translated into mechanical vibrations which are carried about the ring acoustically, that is by compressional waves set up by the supply transducer.

Where selective use of the electrodes is to be made, a selector can be provided very simply as by a pair of contact arms 24, 25 suitably journalled on a central shaft 28 provided with agrip knob (not shown). The arms may be ofspring y construction so that they hold themselves in good contact with the electrodes.

Most piezo-electric material such as quartz, Rochelle salts and the like, are of oriented crystal form and will operate without special electrical pretreatment. The high-dielectric-constant titanates such as the one described above are of unoriented form and for best results should be electrically polarized with a direct current potential applied between the electrode pairs. This potential which can be anything up to about 50 volts per mil of ring thickness is readily impressed by the supply and output units 30, 48 through the same leads that carry the signals. By reason of their fluctuating character the signals are readily combined with and distinguished from the polarizing voltage as is Well known. However after being once polarized, the polarizing voltage can be completely removed without entirely eliminating its efi'ects. This makes a very simple type of installation.

A convenient thickness for ring H.) is about 12-20 mils, but this dimension is not critical. Where high-dielectric-constant titanates are used over extensive temperature ranges, the mixed compositions described in Burnham et al. application Serial No. 540,270, filed June 14, 1944, are preferred.

Fig. 2 shows a similar signal delaying device using a magneto-strictive ring of magnetic ma.- terial. One highly effective form of ring is made by suitabl molding a zinc-nickel ferrite as described for example in the monograph New Developments in Ferromagnetic Materials by J. L. Snoek, published 1947 by the Elsevier Publishing Company, New York, pages 77 to 98.

Around the ring 60 are wound a plurality of signal transducers shown as coils 62, 63', 64, 65. These can be used either to deliver signals to the ring or away from the ring, as described in Patent No. 2,495,740. For best results the ring 3 60 should be magnetically polarized. In this form of the invention, the signals are also carried by acoustic vibration in the ring.

The rings of the present invention can be conveniently held in place in any desired manner. Thus the electrodes of the construction of Fig. 1 can carry projections that are readily soldered or otherwise, secured to a 'holder mount. The ring o f Fig.- 2 can beheld by the projecting coil ends, or if desired, the coils of this construction can be wound on bobbins built around a portion of the ring and used as holding means. Losses due to the mounting are relatively' small.

A feature of the present inventionisthesimplicity with which the signal:delayiisprovided.t

The rings themselves are even "JILOIB :;.compact than the elongated prior art delay devices .such

as shown in Patent No. 2,495,740. Furthermore no precautions need be taken with respect" to undesired end reflections, since the rings do not shi s thes ref ections. Eu thermo mani .l teblesemctmdevices are much pler. moonst ct for. the circularly.distributedeontactsof v a as againstthe. IDW of, contacts needed with elong te d ay.,d vices.

7 Instead of providing, a limited number, of. electrode pairs as shown in.Fig.. 1, for example, the ring Loan be completely, filledwith: transducers .grelectrodes cr wded to thers. cl ly sired.

The,mean eflectiv e diametersof the rings of Figs, 1 and .2 can be conveniently made from abontg inchto about 3 or moreinches. The idth ofthe ring, that.is the .differencebetween errand innerra itshould be relativ ly small. ,;.a 9gt- /e..te EA inch ore an pl As many apparently idelydifferent embodimeats Qf.. hi$ in ention may. be .madewithout .de-

.r 'ne.. .r9m. he sp ri -m1 wD her-eof,"i a ;toz.b.e understood I that t e invention i n it d to the speeifi embodim nt hereof ept sidel n th appended claims.

s .claimedis: gnal delaying device having, a. stationary .rillg ZQPBQ tran ducer a ap d to functionasparallel acoustic paths provided by the ring shape of the carrier.

2. The combination as defined by claim 1 in which the carrier is a ring of alkaline earth metal titanate in which the alkaline earth metal includes at least one of the class consisting of strontium and barium.

1' 3,. The .combination-gas"udefined by claim 1 in .which the carrier is'a-ri-ng ofmagne'tostrictive material.

4. The combination as defined by claim 2 in whicheachtranslator is in the form of a pair of electro'des on'opposite sides of the ring portion .to which it linked.

l flhea-combination as defined by claim 2 in Whichixthe-ring-isflat and each translator is in .the vformeofna pair of electrically conductive coatings opposite each other on the opposed .faceszorthe ring.

6. The combinationas defined by claim 5 and further including a a movable 7 contact structure having: contacts .pivotally. held for adjustment to engage .the coatings of the; different .output signal pattern.

.7 A ,unitary electronic. signal .delaying device for interposing a predetermined time 1 delay in the transfer of an-ultra high .frequencyspulse signal wave comprising, astationary solid ring- .shaped transducer, -an input signal translator connected about one portion of said-;ringshaped transducer for receiving electronic signals and translating them into corresponding =mechan-ical signals in the body-ofisaid transducenan out- ,put signal translator connected :on a :remote portion of said ring-shaped transducer for reoonverting said mechanical signals transferred :through :the body of said transducer into electronic signals .Which I correspond :to but are delayed in time with respect to saidinputisignals.

8. The ..combination .set =.forth in claim '7 in which nausecond output signal translator is -:-positioned on said ring-shaped transducer at a point remote from said input signal translator and said other output signal translator, and means for selectively connecting either or -:said output signal translators .into an electronic network .for 'retransfer of said :delayed signal.

;M. JALLISON.

References Cited in the .1116 or this patent UNITED -STATES PATENTS .Number 

